faniRN
A. r = 21 cm luas = phir^2 => 3,14 x 21^2 = 1384,74 cm^2 keliling = 2 x phi x r => 2 x 3,14 x 21 = 131,88 b. r = 30 cm luas = 3,14 x 30^2 = 2826 cm^2 keliling = 2 x 3,14 x 30 = 188,4 c. r = 49 luas = 3,14 x 49^2 = 7539,14 cm^2 keliling = 2 x 3,14 x 49 = 307,72
luas = phir^2 => 3,14 x 21^2 = 1384,74 cm^2
keliling = 2 x phi x r => 2 x 3,14 x 21 = 131,88
b. r = 30 cm
luas = 3,14 x 30^2 = 2826 cm^2
keliling = 2 x 3,14 x 30 = 188,4
c. r = 49
luas = 3,14 x 49^2 = 7539,14 cm^2
keliling = 2 x 3,14 x 49 = 307,72